Co-pending applications Ser. No. 740,450, now U.S. Pat. No. 4,147,680 and Ser. No. 740,454, now abandoned, relate to a process for the preparation of dispersions of ionic polyisocyanate polyaddition products in polyhydroxyl compounds, in which the polyaddition products are produced in situ in the polyhydroxyl compound used as dispersing agent.